Chinese siblings with hereditary medullary thyroid carcinoma caused by RET mutation: implications for RET oncogene detection.

BACKGROUND: Hereditary medullary thyroid carcinoma (MTC) is mainly caused by germline mutations in the RET proto-oncogene, which accounts for 20-30% of all MTC according to foreign studies. However, no English literatures have reported Chinese hereditary MTC. Here, we reported two Chinese brothers with MTC that caused by germline RET mutation. CASE PRESENTATION: The younger brother was diagnosed with MTC at 29 years ago and suffered recurrence more than 10 years. For elder brother, the diagnosis of MTC was made by postoperative pathological examination at age 61. Both patients received total thyroidectomy and lymph node dissection. Since they had a significant family history for MTC, genetic detection was performed and identified a germline mutation in RET exon 10 (p.C620Y). This mutation was also detected in their offspring, indicating a moderate risk of MTC. CONCLUSIONS: This is the first report presenting a Chinese family with hereditary MTC caused by the RET p.C620Y variant. This case series emphasize the importance of genetic detection of RET proto-oncogene for MTC patients, and bring out managements for individuals after detection of RET mutations.

Multiple endocrine neoplasia 2A (MEN 2A) syndrome.

INTRODUCTION: In the MEN 2A syndrome, which is the most common of the three types of MEN, three endocrine systems are affected simultaneously or subsequently by the development of tumours manifested by medullary thyroid gland carcinoma, pheochromocytoma (often bilateral) and hyperparathyroidism. MATERIAL AND METHODS: 27 patients from 3 families affected by MEN 2A syndrome were examined clinically (by detecting the effects of catecholamine overproduction), biochemically (screening for metanephrine and normetanephrine in the serum), visualization (CT, MRI, MIBG, PET CT) and some of them also genetically (DNA fragment analysis obtained by PCR amplification). RESULTS: Familial incidence of pheochromocytoma was confirmed in 10 patients (4 males, 5 females and one girl) aged 6 to 54 years (average 22.8 years) . In 5 patients, the pheochromocytoma occurred on both sides, in one patient, with genetically proved MEN 2A syndrome, only one adrenal gland was affected by pheochromocytoma. In 10 patients, mutations were detected in the exon 10, 11 and 16 RET of the proto-oncogene in the centromeric region of the 10th chromosome. After proper preparation, 5 patients underwent bilateral adrenalectomy (unilateral adrenalectomy in one patient). Histological examination of the removed tumours in all cases excluded the malignant pheochromocytoma.The first of the operated patients (54 yr) died after surgery for cardiovascular failure. Others have lived 5 to 15 years after bilateral adrenalectomy without signs of local recurrence of the disease, and have no clinical signs of over-production of catecholamines. CONCLUSION: Bilateral pheochromocytoma and thyroid carcinoma are indications for detailed clinical and genetic examination of all family members. Bilateral adrenalectomy with lifetime supplementation of adrenal hormones is indicated in symptomatic patients and/or patients asymptomatic with tumours larger than 3 cm in diameter (Tab. 1, Fig. 11, Schema 1, Ref. 31).

Gallium-68 Dotatate PET/CT is superior to other imaging modalities in the detection of medullary carcinoma of the thyroid in the presence of high serum calcitonin.

OBJECTIVE: Medullary carcinoma of the thyroid (MTC) is a rare neuroendocrine tumour (NET) that expresses somatostatin receptors on the cell membrane and secretes calcitonin. Surgery is the primary curative modality but is achieved only when the diagnosis is timely so there is a high rate of persistent and recurrent disease indicated by a rise in the serum calcitonin levels. Successful management of recurrent disease requires accurate localisation with cross sectional and functional imaging. The introduction of gallium-68-Dotatate ((68)Ga-Dotatate) peptides positron emission tomography/computerized tomography (PET/CT) has significantly improved the detection of NET and has been reported as a valuable adjunct in MTC localisation. We retrospectively reviewed our cases of MTC to correlate the detectability of (68)Ga-Dotatate in relation to calcitonin levels and assess suitability of inoperable patients for peptide receptor radionuclide therapy (PRRT). SUBJECTS AND METHODS: Seven patients (age range 31-66 years, M:F 3:4) with raised calcitonin (mean=7,143pg/mL) were referred for (68)Ga-Dotatate PET/CT scan for localisation of persisting recurrent MTC. Six patients were known to have MTC treated with thyroidectomy and one patient was presenting for the first time. All patients had multiple imaging including ultrasound (US), CT, magnetic resonance imaging (MRI), fluorine-18-fluorodeoxyglucose ((18)F-FDG) PET/CT and iodine-123-metaiodobenzylguanidine ((123)I-MIBG). Positive findings were defined as areas of increased uptake other than the organs of normal distribution and were correlated with results of biopsies, other imaging, long term monitoring of calcitonin and clinical follow up. RESULTS: In 6/7 patients with very high serum calcitonin (range= 672-37,180, mean=8,320pg/mL) (68)Ga-Dotatate PET/CT confirmed the presence of active disease seen on other modalities or detected hitherto unsuspected lesions. In at least 3 cases, (68)Ga-Dotatate PET/CT showed many more lesions compared to other imaging combined. In 1/7 patient (68)Ga-Dotatate PET/CT was negative in line with a relatively low calcitonin level (80pg/mL) and negative disease on fine needle aspiration. CONCLUSION: (68)Ga-Dotatate PET/CT is an effective tool for localising metastatic spread of MTC. It appears to be most effective in the presence of higher levels of serum calcitonin, probably in excess of 500pg/mL. The results of our small cohort had an impact on staging and management with the introduction of peptide receptor radionuclide therapy for inoperable disease.

Ultrasonography should not guide the timing of thyroidectomy in pediatric patients diagnosed with multiple endocrine neoplasia syndrome 2A through genetic screening.

BACKGROUND: American Thyroid Association (ATA) guidelines suggest that thyroidectomy can be delayed in some children with multiple endocrine neoplasia syndrome 2A (MEN2A) if serum calcitonin (Ct) and neck ultrasonography (US) are normal. We hypothesized that normal US would not exclude a final pathology diagnosis of medullary thyroid cancer (MTC). METHODS: We retrospectively queried a MEN2A database for patients aged<18 years, diagnosed through genetic screening, who underwent preoperative US and thyroidectomy at our institution, comparing preoperative US and Ct results with pathologic findings. RESULTS: 35 eligible patients underwent surgery at median age of 6.3 (range 3.0-13.8) years. Mean MTC size was 2.9 (range 0.5-6.0) mm. The sensitivity of a US lesion≥5 mm in predicting MTC was 13% [95% confidence interval (CI) 2%, 40%], and the specificity was 95% [95% CI 75%, 100%]. Elevated Ct predicted MTC in 13/15 patients (sensitivity 87% [95% CI 60%, 98%], specificity 35% [95% CI 15%, 59%]). The area under the receiver operating characteristic curve (AUC) for using US lesion of any size to predict MTC was 0.50 [95% CI 0.33, 0.66], suggesting that US size has poor ability to discriminate MTC from non-MTC cases. The AUC for Ct level at 0.65 [95% CI 0.46, 0.85] was better than that of US but not age [AUC 0.62, 95% CI 0.42, 0.82]. CONCLUSIONS: In asymptomatic children with MEN2A diagnosed by genetic screening, preoperative thyroid US was not sensitive in identifying MTC of any size and, when determining the age for surgery, should not be used to predict microscopic MTC.

Is basal ultrasensitive measurement of calcitonin capable of substituting for the pentagastrin-stimulation test?

OBJECTIVE: To evaluate a second-generation assay for basal serum calcitonin (CT) measurements compared with the pentagastrin-stimulation test for the diagnosis of inherited medullary thyroid carcinoma (MTC) and the follow-up of patients with MTC after surgery. Recent American Thyroid Association recommendations suggest the use of basal CT alone to diagnose and assess follow-up of MTC as the pentagastrin (Pg) test is unavailable in many countries. DESIGN: Multicentric prospective study. PATIENTS: A total of 162 patients with basal CT <10 ng/l were included: 54 asymptomatic patients harboured noncysteine 'rearranged during transfection' (RET) proto-oncogene mutations and 108 patients had entered follow-up of MTC after surgery. MEASUREMENT: All patients underwent basal and Pg-stimulated CT measurements using a second-generation assay with 5-ng/l functional sensitivity. RESULTS: Ninety-five per cent of patients with basal CT ≥ 5 ng/l and 25% of patients with basal CT <5 ng/l had a positive Pg-stimulation test (Pg CT >10 ng/l). Compared with the reference Pg test, basal CT ≥ 5 ng/l had 99% specificity, a 95%-positive predictive value but only 35% sensitivity (P < 0.0001). Overall, there were 31% less false-negative results using a 5-ng/l threshold for basal CT instead of the previously used 10-ng/l threshold. CONCLUSION: The ultrasensitive CT assay reduces the false-negative rate of basal CT measurements when diagnosing familial MTC and in postoperative follow-up compared with previously used assays. However, its sensitivity to detect C-cell disease remains lower than that of the Pg-stimulation test.

PET imaging of medullary thyroid carcinoma in MEN2A transgenic mice using 6-[(18)F]F-L-DOPA.

PURPOSE: 6-[(18)F]Fluoro-3,4-dihydroxy-L-phenylalanine (6-[(18)F]F-L-DOPA) is increasingly used for PET imaging of neuroendocrine tumours. In this study, we investigated the use of 6-[(18)F]F-L-DOPA to detect and to monitor the progression of medullary thyroid carcinoma (MTC) in a genetically engineered mouse model of multiple endocrine neoplasia type 2A (MEN2A). METHODS: Dynamic [(18)F]FDG and 6-[(18)F]F-L-DOPA small animal PET scans were acquired during 60 or 90 min in 8- to 20-month-old MEN2A transgenic mice. The kinetics of 6-[(18)F]F-L-DOPA, standardized uptake values (SUV) at 60 min and tumour volumes were recorded. The detection of MTCs using PET was confirmed by autopsy and histological analysis. RESULTS: 6-[(18)F]F-L-DOPA performs better than [(18)F]FDG for MTC detection in this transgenic mouse model. Uptake kinetics of 6-[(18)F]F-L-DOPA in MTCs are very different between mice but, in all cases, high contrast could be observed. Furthermore, 6-[(18)F]F-L-DOPA can detect tumours with sizes (1.8 mm(3)) that are near the resolution limit of PET, whereas they were undetectable by autopsy at the macroscopic level. CONCLUSION: 6-[(18)F]F-L-DOPA PET imaging can monitor the progression of MTCs in a genetically engineered mouse model.

Contrast-enhanced ultrasound for imaging of adrenal masses.

PURPOSE: The number of incidentally discovered adrenal masses is growing due to the increased use of modern high-resolution imaging techniques. However, the characterization and differentiation of benign and malignant adrenal lesions is challenging. This study aimed to evaluate contrast-enhanced ultrasound for the characterization of adrenal masses. MATERIALS AND METHODS: We studied 58 patients with adrenal masses detected with computed tomography, magnetic resonance imaging, or ultrasound. 7 patients had bilateral adrenal lesions. Contrast-enhanced ultrasound was performed using high-resolution ultrasound (3.5 - 7 MHz) and intravenous injection of 2.4 ml SonoVue. The contrast enhancement pattern of all adrenal lesions was documented. RESULTS: The 18 malignant adrenal tumors were significantly larger at the time of diagnosis compared to the 40 benign lesions (p < 0.03). The majority of benign adrenal lesions (37 / 40) had a nonspecific type of contrast enhancement (24 / 40) or a peripheral to central contrast filling (13 / 40) described as the iris phenomenon. Similar findings were observed in malignant adrenal tumors: most malignant lesions also showed nonspecific (6 / 18) or peripheral to central contrast filling (9 / 18). Peripheral to central contrast filling had 50 % sensitivity (26 - 74 %) and 68 % specificity (51 - 81 %) for indicating malignancy. CONCLUSION: Contrast-enhanced ultrasound facilitates the visualization of vascularization even in small adrenal masses, but it does not help to distinguish malignant and benign lesions.

Multiple endocrine neoplasia type 2a and germ line C634G RET mutation diagnosed in an 80-year-old patient.

An 80-year-old man presented with progressive fatigue. Blood tests showed that serum calcium was increased (2.93 mmol/l, normal range 2.20-2.55 mmol/l) and serum concentration of intact parathyroid hormone (iPTH) inappropriately high (198 pg/ml, normal range 15-85 pg/ml). Neck ultrasonography and Tc-MIBI scintigraphy revealed a right parathyroid adenoma and a multinodular goiter. Serum calcitonin was significantly increased (220 pg/ml, normal range<10 pg/ml). Concomitantly, a chest-abdominal computed tomography was performed and revealed a 22 mm right adrenal incidentaloma. The urinary catecholamines and metabolites were two-fold above the upper limit of normal. After right adrenalectomy which confirmed the diagnosis of pheochromocytoma, the patient underwent total thyroidectomy with dissection of the central lymph node compartment and right parathyroidectomy. On histopathologic examination, both thyroid lobes presented 13 foci of MTC without lymph node metastasis and the parathyroid gland presented a benign adenoma without hyperplasia. The patient underwent screening and genetic testing revealing a germ line C634 G RET mutation. The diagnosis of Men2a at the age of 80 years and the absence of lymph node metastasis of the multiple MTC in a carrier of C634G mutation were unusual and argued for the possible role of genetic modifier(s) in this MEN 2a patient.

Multiple endocrine neoplasia type 2A syndrome (MEN2A) and usefulness of 68Ga-DOTATATE PET/CT in this syndrome.

AIM: The aim of this study was to evaluate a new imaging method 68Ga-DOTATATE PET/CT as an alternative method to diagnose evidence of neuroendocrine tumors or their metastasis (if any) in patient with MEN 2A. METHODS: Three patients( 2F, 1M; age 28,46 and 50 years) with MEN 2A syndrome who underwent 68Ga-DOTATATE PET/CT scan were prospectively evaluated. PET/CT images were analyzed with measurement of maximum standardized uptake value (SUVmax). RESULTS: All patients had adrenal masses with increased uptake of 68Ga-DOTATATE (first case adrenal mass SUVmax: 9,1, second case adrenal mass SUVmax: 32,4(right), 30,3(left) and third case SUVmax:12,4). All of the patients had medullary thyroid carcinoma with increased uptake of 68Ga-DOTATATE (first case SUVmax: 3,3 second case SUVmax:7,7 and third case SUVmax: left thyroid nodule: 19,4, right thyroid nodule: 21,2). Third case has a parathyroid adenoma with SUVmax: 2,8. CONCLUSIONS: New imaging method 68Ga-DOTATATE PET/CT may be an alternative method to diagnose MEN 2A patients. 68Ga-DOTATATE PET/CT can give a great opportunity to detecting the multiple neoplasia like MEN 2A with only one session. KEY WORDS: MEN 2A syndrome, 68Ga-DOTATATE PET/CT, Neuroendocrine tumors.

Use of Dexmedetomidine in a Parturient With Multiple Endocrine Neoplasia Type 2A Undergoing Adrenalectomy and Thyroidectomy: A Case Report.

Dexmedetomidine is a selective α2-agonist, frequently used in perioperative medicine as anesthesia adjunct. The medication carries a Food and Drug Administration pregnancy category C designation and is therefore rarely used for parturients undergoing nonobstetric surgery. We are reporting the use of dexmedetomidine in the anesthetic management of a parturient undergoing minimally invasive unilateral adrenalectomy for pheochromocytoma during the second trimester of pregnancy. Additionally, because of the multiple endocrine neoplasia type 2A constellation with diagnosis of medullary thyroid cancer, the patient underwent a total thyroidectomy 1 week after the adrenalectomy.

Papillary thyroid cancer in childhood: is parental screening helpful?

BACKGROUND: Familial non-medullary thyroid cancer (FNMTC) mandates family screening with ultrasound; however, the need for screening paediatric thyroid cancer with no family history has not been addressed. METHODS: This study conducted a retrospective cohort study in a tertiary hospital. The study group is composed of patients ≤18 years undergoing surgery for papillary thyroid cancer (PTC) from 2008 to 2014. RESULTS: During the study period, 15 paediatric patients had PTC. Only one patient had a prior family history of PTC involving two second-degree relatives. Of the 30 parents, four were lost to follow-up, with the remaining 26 undergoing screening thyroid ultrasound. Nodular thyroid disease was documented in eight ultrasounds performed. Subsequently, one has not undergone fine-needle biopsy, five were benign and two underwent surgical resection: one having a benign follicular adenoma and the other a papillary microcarcinoma with nodal micrometastasis. CONCLUSIONS: Routine ultrasound screening of parents of children presenting with PTC and no family history do not demonstrate an increased incidence of FNMTC. Screening of affected families is likely to demonstrate the expected background incidence of nodular thyroid disease and incidental papillary microcarcinoma. As such, it is unlikely to be useful.

Disseminated medullary thyroid carcinoma despite early thyroid surgery in the multiple endocrine neoplasia-2A syndrome.

A 51/2-year-old boy, with a family history of multiple endocrine neoplasia (MEN)-2A syndrome, was evaluated for presence of MEN-2A and medullary thyroid carcinoma (MTC). DNA diagnostics confirmed MEN-2A. Basal (360 ng/L) and pentagastrin stimulated (430 ng/L) calcitonin (CT) levels were slightly elevated, plasma carcinoembryonic antigen (CEA) was normal. Within a year both tumor markers increased and total thyroidectomy was performed. Histologic examination did not show MTC. In the following years, both tumor markers increased progressively but despite the use of multiple imaging techniques no metastases were localized. After 6 years, biopsy of a palpable lymph node showed MTC. The boy was treated with total cervical, suprahyoidal, and mediastinal lymph node dissection, showing MTC in almost all nodes. Again, the tumor markers remained high. At this point in time, the disadvantages of further medical interventions were outweighed against the chance for cure and it was decided to shift the goal of treatment toward palliation rather than cure. At the last visit the boy was clinically well with persistent extremely high levels of plasma CEA and CT. In conclusion, when prophylactic thyroidectomy in the MEN-2A syndrome has failed, it may be best to withdraw from further interventions to prevent more damage.

[(123)I]metaiodobenzylguanidine and [(111)In]octreotide uptake in begnign and malignant pheochromocytomas.

Selecting the appropriate approach for resection and follow-up of pheochromocytomas (PCCs) is highly dependent upon reliable localization and exclusion of multifocal, bilateral, or metastatic disease. Metaiodobenzylguanidine (MIBG) scintigraphy was developed for functional localization of catecholamine-secreting tissues. Somatostatin receptor imaging (SRI) has a high sensitivity for localizing head and neck paragangliomas, but studies of intraabdominal PCCs are rare. In this study we review our experience of [(123)I]MIBG and SRI, performed since 1983 and 1989, respectively, in the work-up of primary and recurrent PCCs. Scintigraphic results were correlated with catecholamine secretion, size and site, malignancy, associated tumor syndromes, and morphological features. [(123)I]MIBG scans were performed in a total of 75 patients, in 70 cases before resection of primary PCCs and in 5 cases because of recurrent disease. Ninety-one PCCs were resected. The overall detection rates were 83.3% and 89.8% for PCCs larger than 1.0 cm. Multifocal disease was detected in 4 patients with [(123)I]MIBG. [(123)I]MIBG uptake correlated with greater size of PCC (r = 0.33; P = 0.008) and greater concentration of plasma epinephrine (r = 0.32; P = 0.006). [(123)I]MIBG-negative PCCs (n = 14) had significantly (P = 0.01) smaller diameters than [(123I)]MIBG-positive tumors. Furthermore, [(123)I]MIBG uptake was significantly higher in unilateral (P = 0.02), benign (P = 0.02), sporadic (P = 0.02), intraadrenal (P = 0.02), and capsular invasive (P = 0.03) PCCs than in bilateral, malignant, MEN2A/2B-related, extraadrenal, and noninvasive PCCs, respectively. The detection rate of SRI was only 25% (8 of 32) for primary benign PCCs. In 14 patients metastases occurred, which were effectively visualized with [(123)I]MIBG in 8 of 14 cases. SRI was able to detect metastases in 7 of 8 cases, including 3 [(123)I]MIBG-negative metastatic cases. In addition, [(123)I]MIBG and SRI detected 2 recurrences. In conclusion, [(123)I]MIBG uptake is correlated with the size, epinephrine production, and site of PCCs. Its role in bilateral and MEN2A/2B-related PCCs seems limited. In cases of recurrent elevation of catecholamines, localization of metastases and/or recurrence should be attempted with [(123)I]MIBG scintigraphy. In suspicious metastatic PCCs, SRI might be considered to supplement [(123)I]MIBG scintigraphy.

Multiple endocrine neoplasia 2A syndrome presenting as peripartum cardiomyopathy due to catecholamine excess.

We report the case of a 24-year-old female with a history of medullary thyroid carcinoma who presented at 38 weeks gestation with acute chest pain and shortness of breath. She was found to be in pulmonary edema and respiratory failure. An emergency cesarean section was performed. Subsequently, an echocardiogram revealed an ejection fraction of 10%. After medical therapy with digoxin, milrinone, captopril and diuretics, her condition improved rapidly and a repeat echocardiogram showed that the left ventricular function had normalized. Diagnosis of pheochromocytoma was made by urine and plasma catecholamine measurements. Magnetic resonance imaging revealed a 3.7 cm left adrenal mass. Increased uptake activity was seen in the same region by an (131)I-metaiodobenzylguanidine (MIBG) scan. The patient underwent successful surgical resection of the pheochromocytoma. Subsequent DNA analysis revealed that the patient had a mutation of the RET proto-oncogene. The same mutation was also found in several of her family members. In summary, we report a case of multiple endocrine neoplasia 2A presenting as peripartum cardiomyopathy and cardiovascular collapse. Pheochromocytoma should be considered as a potential cause of peripartum cardiomyopathy.

FDG PET imaging in hereditary thyroid cancer.

AIM: To report the role of different imaging methods in staging individuals with multiple endocrine neoplasia 2A (MEN2A) or familial medullary thyroid carcinoma (FMTC). MATERIAL AND METHODS: Fourteen newly diagnosed gene carriers underwent cervical ultrasound scanning (US), cervical and mediastinal CT, MRI and whole-body meta-[131I]iodobenzylguanidine (MIBG) scintigraphy and [18F]fluorodeoxyglucose (FDG) PET scanning. RESULTS: US identified seven true primary cancer. CT and MRI located only tumors > or =5 mm in diameter. MIBG scintigraphy and FDG PET could not identify MTC foci within the thyroid. Whole-body FDG PET identified two true-positive and one false-positive lymph node metastases. MIBG scintigraphy did not identify lymph node metastases. Total thyroidectomy was performed in 12 cases, and subtotal thyroidectomy in two subjects. CONCLUSIONS: Whole-body FDG PET and cervical US help stage individuals carrying mutant genes verifying MEN2A or FMTC.

Detection of hepatic metastasis from medullary thyroid cancer with Tc-99m-MIBI scintigraphy in a patient with Sipple's syndrome.

We report a case of Sipple's syndrome with a hepatic tumor. A 28-year-old male with medullary thyroid cancer and bilateral pheochromocytomas was diagnosed as having Sipple's syndrome. The hepatic tumor was found to be hypervascular by means of a dynamic abdominal CT scan. An I-131-MIBG scan showed no increased accumulation in the tumor. A whole body Tc-99m-MIBI scan had shown, however, increased accumulation in the tumor by 10 minutes after i.v. Tc-99m-MIBI. The hepatic tumor was diagnosed histologically as a metastasis from the medullary thyroid cancer. To our knowledge, there have been no previous reports of increased Tc-99m-MIBI accumulation in hepatic metastases from medullary thyroid cancer.

I-131 MIBG and bone scintigraphy in a patient with MEN.

The case of a patient with MEN is described. Emphasis is placed on the role of I-131 MIBG and bone scintigraphy as a part of the diagnostic and follow-up procedures.